CONNECTIONS, 7TH EDITION:
BIOLOGY CHAPTER 21: NUTRITION AND DIGESTION
>Herbivore - :An animal that eats only plants or algae.
> carnivore - :An animal that mainly eats other animals.
> omnivore - :An animal that eats animals as well as plants or algae.
> suspension feeder - :An aquatic animal that sifts small food particles from the
water.
> substrate feeder - :An organism that lives in or on its food source, eating its way
through the food.
> bulk feeder - :An animal that eats relatively large pieces of food.
> ingestion - :The act of eating; the first main stage of food processing in animals.
> digestion - :The mechanical and chemical breakdown of food into molecules
small enough for the body to absorb; the second main stage of food processing in
animals.
> absorption - :The uptake of small nutrient molecules by an organism's own body;
the third main stage of food processing, following digestion.
> elimination - :The passing of undigested material out of the digestive
compartment; the fourth and final stage of food processing in animals.
> gastrovascular cavity - :A digestive compartment with a single opening, the
mouth; may function in circulation, body support, waste disposal, and gas
exchange, as well as digestion.
> mouth - :An opening through which food is taken into an animal's body.
, > alimentary canal - :A digestive tract consisting of a tube running between a
mouth and an anus.
> pharynx - :The organ in a digestive tract that receives food from the oral cavity;
in terrestrial vertebrates, the throat region where the air and food passages cross.
> esophagus - :The channel that conducts food by peristalsis, usually from the
pharynx to the stomach.
> crop - :A pouchlike organ in a digestive tract where food is softened and may be
stored temporarily.
> stomach - :A pouch-like organ in a digestive tract that grinds and churns food
and may store it temporarily.
> gizzard - :A pouch-like organ in a digestive tract where food is mechanically
ground.
> anus - :The opening through which undigested materials are expelled.
> oral cavity - :The mouth of an animal.
> peristalsis - :Rhythmic waves of contraction of smooth muscles. It propels food
through a digestive tract and also enables many animals, such as earthworms, to
crawl.
> sphincter - :A ringlike valve, consisting of modified muscles in a muscular tube,
that regulates passage between some compartments of the alimentary canal.
> salivary glands - :Glands associated with the oral cavity that secrete substances
to lubricate food and begin the process of chemical digestion.
> gastric juice - :The collection of fluids (mucus, enzymes, and acid) secreted by
the stomach.
> gastrin - :A digestive hormone that stimulates the secretion of gastric juice.